[0001] This invention relates to an exposure apparatus and, more particularly, to an exposure
apparatus for transferring and printing an image of an original, such as a mask, onto
a workpiece such as a semiconductor wafer, with high precision.
[0002] With recent increasing degree of integration of semiconductor integrated circuit,
in an exposure apparatus (aligner) for manufacture of the same, further enhancement
of transfer precision is required. As an example, for an integrated circuit of 256
megabit DRAM, an exposure apparatus capable of printing a pattern of a linewidth of
0.25 µm order is necessary.
[0003] As such super-fine pattern printing exposure apparatus, an exposure apparatus which
uses orbit radiation light (SOR X-rays) has been proposed.
[0004] The orbit radiation light has a sheet beam shape, uniform in a horizontal direction.
Thus, for exposure of a plane of certain area, many proposals have been made, such
as follows:
(1) Scan exposure method wherein a mask and a wafer are moved in a vertical direction
whereby the surface is scanned with X-rays of sheet beam shape in a horizontal direction;
(2) Scan mirror exposure method wherein X-rays of sheet beam shape are reflected by
an oscillating mirror whereby a mask and a wafer are scanned in a vertical direction;
and
(3) Simultaneous exposure method wherein X-rays of sheet beam shape in a horizontal
direction are diverged in a vertical direction by an X-ray mirror having a reflection
surface machined into a convex shape, whereby an exposure region as a whole is irradiated
simultaneously.
[0005] The inventors of the subject application have cooperated to devise such a simultaneous
exposure type X-ray exposure apparatus, which is disclosed in Japanese Laid-Open Patent
Application No. 243519/1989.
[0006] In this type of exposure apparatus, exposure light (X-ray) has uniform illuminance
in a horizontal direction (hereinafter "X direction"). However, in a vertical direction
(hereinafter "Y direction"), it has non-uniform illuminance such as depicted by an
illuminance distribution curve 1i in Figure 3A, for example, wherein the illuminance
is high at a central portion and decreases with an increasing spacing therefrom. In
the proposed apparatus, a blocking member having a rectangular opening (shutter aperture)
is used, and the relationship of the time moment (t) of passage and the position in
the Y direction of each of two edges, of four edges defining the opening, is controlled
independently as depicted in Figure 3B, whereby the exposure time (ΔT) at each portion
in an exposure region is controlled, as depicted in Figure 3C. More specifically,
the time period from the passage of a leading edge 1a of the blocking member (the
preceding one of the two edges with respect to the movement direction of the blocking
member), for allowing transmission of the exposure light (X-rays), to the passage
of a trailing edge 1b of the opening of the blocking plate (the succeeding edge with
respect to the movement direction of the blocking member), for interception of the
exposure light, is controlled to thereby attain correct and uniform exposure of the
whole exposure region. In that case, the exposure quantity control is effected on
the basis of an X-ray illuminance distribution curve (hereinafter "profile") in the
Y direction, such as depicted in Figure 3A, as measured in the exposure region.
[0007] In this X-ray exposure apparatus, however, any deviation between the aforementioned
profile and an edge drive curve produces a non-negligible effect upon the transfer
precision.
[0008] For example, if edge drive curves as depicted by solid lines 1a and 1b in Figure
3B, corresponding to the profile of solid line 1i in Figure 3A, shift by Δy to the
positions of broken lines 2a and 2b in Figure 3B, respectively, corresponding to the
profile of broken line 2i in Figure 3A, then the illuminance I of the exposure light
at a position y changes by "(dI/dy) x Δy". Accordingly, in order to suppress the change
in illuminance I to a quantity not greater than 0.1 %, the following relation has
to be satisfied:

More particularly, if the view-angle size of the exposure region in the Y direction
is 30 mm, if the profile such as depicted by the solid line 1i in Figure 3A is represented
by a quadratic function which is vertically symmetric with respect to a center line
and if the lowest illuminance is 80 % of the highest illuminance, then it follows
that:

Thus, it is seen that, in order to suppress non-uniformness in illuminance to a quantity
not greater than 0.1 %, the shift Δy in relative position of the exposure light to
the exposure region has to be kept at a quantity not greater than 40 microns.
[0009] The deviation of the edge drive curve or profile may result from a change in the
relative attitude of a SOR device and a major assembly of the exposure apparatus,
in a case of SOR X-ray exposure apparatus, and, generally, it may be attributable
to an error between coordinate axes of a wafer stage and an edge driving system.
[0010] EP-A-0357425 describes an exposure apparatus in which the movement of a leading edge
of a shutter aperture through an exposure zone is controlled independently of the
movement of a trailing edge of the shutter aperture through the exposure zone so as
to enable a uniform exposure within the exposure zone.
[0011] EP-A-0421746 which published after the filing date of the present application describes
an exposure apparatus where, again, movement of a leading edge of a shutter through
an exposure zone is controlled independently of movement of the trailing edge of the
shutter through the same exposure zone. Detectors placed outside the exposure zone
are used to detect a change in the relative position of the exposure zone and the
radiation source. The drive of the shutter is corrected in accordance with the detected
change in the relative position of the exposure zone and the radiation source.
[0012] The inventors of the subject application have made investigations into an exposure
apparatus of the aforementioned type to attain further enhancement of the transfer
precision, and have found that a change in the relative position of the exposure region
and the exposure light provides a non-negligible effect on the transfer precision.
Particularly, in the proximity exposure process, a change in angle of incidence of
the exposure light to the exposure region results in degradation of the superposing
precision.
[0013] For example, if the proximity gap G between a mask and a wafer is 50 microns, then,
in order to suppress a superposition error Δδ due to a change in the angle of incidence
to a quantity not greater than 0.002 micron, the change Δθ in the angle of incidence
has to be suppressed to satisfy:

Namely, it has to be suppressed to a quantity not greater than 4x10
-5 rad.
[0014] Further, if the exposure light has a divergent angle, the angle of incidence of the
exposure light to the exposure region changes with the shift Δy of the relative position
as described above. If the interval between the surface to be exposed and the point
of divergence (e.g. the position of incidence of X-rays upon a divergence convex mirror
of a SOR X-ray exposure apparatus) is 5 m, then the quantity Δθ of change in the angle
of incidence is given by:

From this change Δθ in the angle of incidence, the above-described superposition
error Δδ results. The superposition error Δδ in this case appears at different portions
of the surface to be exposed, as as run-out error of distributed transfer magnifications.
From the above equation, it is seen that the change Δy in the relative position has
to be suppressed to a quantity not greater than 0.2 mm.
[0015] Further, if in the positional relationship between the exposure light and the exposure
region there occurs a rotational deviation Δω
z about an axis (Z axis) of the path of the exposure light, then, at a position (X,
Y) on the X-Y plane having an origin on that axis, there are caused an error Δθ in
the angle of incidence as well as an illuminance change ΔI and an error Δδ, equivalently
as there is caused a change Δy wherein Δy = Y·cosω
z.
[0016] As regards the variations such as the relative positional deviation Δy and Δω
z, one which is attributable to an attitude change of the exposure apparatus resulting
from movement of a wafer stage may be of about 200 microns, a displacement resulting
from a temperature change may be of about 10 microns and a displacement resulting
from the vibration of a floor may be of about 2 microns.
[0017] According to one aspect of the present invention, there is provided an apparatus
in accordance with claim 1. The present invention also provides a method in accordance
with claim 13.
[0018] An embodiment of the present invention provides an exposure apparatus by which an
exposure quantity error ΔI and a superposition error Δδ attributable to the rotational
deviation Δω
z can be reduced to thereby attain further enhancement of the transfer precision.
An embodiment of the present invention
[0019] provides an exposure apparatus, comprising: a radiation source with non-uniformness
in illuminance generally in one-dimensional direction with respect to a predetermined
exposure region; exposure quantity correcting means for setting an exposure time distribution
in accordance with the non-uniformness in illuminance so as to assure a substantially
uniform exposure quantity in said exposure region; illuminance distribution measuring
means for measuring an illuminance distribution in said exposure region; computing
means for calculating a constant-illumination line on the basis of a measured data
of said measuring means; and paralleling means for paralleling said constant-illumination
line and a constant-exposure-time line of said exposure quantity correcting means.
[0020] In this structure, the illuminance distribution measuring means serves to measure
an illuminance distribution in the exposure region and an area adjacent thereto, the
computing means serves to calculate a constant-illuminance line on the basis of a
measured illuminance distribution data, and the paralleling means serves to execute
the paralleling between the calculated constant-illuminance line and a constant-exposure-time
line determined by the exposure quantity correcting means. By this paralleling, the
rotational deviation ω
z can be corrected and, therefore, the exposure quantity error ΔI and the superposition
error Δδ attributable to such rotational deviation ω
z can be reduced.
[0021] An embodiment of the present invention provides an exposure method and apparatus
by which uniform exposure is attained and, thus, a resist pattern of uniform linewidth
is assured.
[0022] An embodiment of the present invention provides an exposure apparatus by which an
exposure quantity error ΔI attributable to a relative deviation Δy between the edge
drive curve and the profile can be reduced to thereby enhance the transfer precision.
[0023] An embodiment of the present invention provides an exposure apparatus, comprising:
a radiation source with non-uniformness in illuminance generally in one-dimensional
direction with respect to a predetermined exposure region; illuminance measuring means
for measuring an illuminance distribution in said one-dimensional direction in said
exposure region and in an area adjacent thereto; shutter means having a leading edge
effective to start exposure in said exposure region and a trailing edge effective
to stop the exposure; a memory with a drive table for setting a drive curve for said
leading and trailing edges in accordance with the measured illuminance distribution;
shutter driving means for causing said leading and trailing edges to move through
said exposure region in said one-dimensional direction, independently of each other,
in accordance with said drive table; edge position detecting means for detecting,
with an illuminance detector of said illuminance measuring means and at different
two points spaced in said one-dimension direction, a position of a shadow of one of
said leading and trailing edges; and coordinate conversion means for effecting conversion
of a coordinate system of said drive table and a coordinate system for the positioning
of said illuminance detector during the illuminance distribution measurement, in accordance
with results of the edge position detection.
[0024] With this structure, the position of the shadow of the edge as detected by the illuminance
distribution measuring means with respect to at least two points, spaced in the direction
of illuminance distribution, does correspond to the position of the edge, designated
in terms of the coordinate system of the drive table, as projected upon the coordinate
system used for the measurement of the illuminance distribution.
[0025] Accordingly, it is possible to detect the relationship between the coordinate system
of the drive table and the coordinate system in the measurement of illuminance distribution
and, by converting the coordinate system for the illuminance distribution measurement
into the coordinate system of the drive table, an error between the coordinate systems
of the illuminance distribution measurement and the drive table can be corrected and,
as a result, non-uniformness in exposure (exposure quantity error) ΔI attributable
to such error can be reduced.
[0026] Embodiments of the present invention will now be described, by way of example, with
reference to the accompanying drawings, in which:
[0027] Figure 1 is a schematic and diagrammatic view of an X-ray exposure apparatus according
to an embodiment of the present invention.
[0028] Figure 2 is a perspective view, showing details of an exposure shutter device of
the Figure 1 embodiment.
[0029] Figures 3A - 3C are graphs, respectively, for explaining the operation of the exposure
apparatus of the Figure 1 embodiment, wherein Figure 3A shows an illuminance distribution
(profile) of illumination light, Figure 3B shows shutter drive curves and Figure 3C
shows an exposure time distribution.
[0030] Figure 4 is a flow chart for explaining the coordinate system converting operation
in the exposure apparatus of the Figure 1 embodiment.
[0031] Figure 5 is a flow chart for explaining the paralleling operation in the exposure
apparatus of the Figure 1 embodiment.
[0032] Figures 6A - 6D are schematic views, respectively, for explaining detection of constant-intensity
lines in the exposure apparatus of the Figure 1 embodiment.
[0033] Figure 7 is a schematic view for explaining edge detection in the exposure apparatus
of the Figure 1 embodiment.
[0034] Figures 8 and 9 are graphs, respectively, for explaining the operation of an X-ray
detector for the edge detection, in the exposure apparatus of the Figure 1 embodiment.
[0035] Figure 1 shows a general structure of an X-ray exposure apparatus according to an
embodiment of the present invention. Denoted in the drawing at 101 is a synchrotron
orbit radiation light (SOR X-ray), and denoted at 102 is an exposure mirror having
a reflection surface machined into a convex shape, for expanding the SOR X-ray 101,
of a sheet beam shape elongated in the X (substantially horizontal) direction, in
the Y (substantially vertical) direction. The bundle of X-rays from the exposure mirror
102 diverging in the Y direction is inputted into an exposure apparatus main assembly
100 as an illumination light (exposure beam) 103 for the exposure process.
[0036] In the exposure apparatus main assembly 100, denoted at 104 is as beryllium window
for isolating an exposure X-ray input path, maintained at a high vacuum, and a helium
ambience in a chamber 105, from each other. Denoted at 106 is an auxiliary shutter
unit (movable aperture unit) comprising an endless steel (SUS) belt having openings.
It cooperates with a main shutter unit 107 of a similar structure to provide an exposure
shutter device. Denoted at 108 is a mask having a pattern, to be transferred, formed
thereon by use of an X-ray non-transmissive material such as gold, for example, Denoted
at 109 is a wafer chuck with which a wafer 110, onto which an image of the mask 108
is to be transferred, can be held fixed on a wafer stage that comprises an X stage
121 and a Y stage 122, for example. The wafer 110 is coated with a resist which is
sensitive to X-rays. Denoted at 111 is an alignment optical unit for measuring the
relative positional relationship between the mask 108 and the wafer 110; at 123 is
an X stage motor for driving the X stage 121; at 124 is a Y stage motor for driving
the Y stage 122; at 125 and 126 are motor drivers for the X stage motor 123 and the
Y stage motor 124, respectively; at 127 is a stage actuator control unit for controlling
the operations of the motor drivers 125 and 126, respectively; at 128 is a laser length-measuring
device for measuring the position of the wafer stage; at 129 is a mirror for the laser
length-measurement; and at 130 is a length measuring system control unit. Denoted
at 131 is a central processing unit (CPU) which is communicated with a main controller
191 through a common bus 190, to control the stage actuator control unit 127 and the
measuring system control unit 130.
[0037] Denoted at 151 is an auxiliary shutter motor for driving the auxiliary shutter unit
106, and denoted at 152 is a main shutter motor for driving the main shutter unit
107. Denoted at 153 and 154 are motor drivers, respectively, for driving the motors
151 and 152 in accordance with the number of pulses outputted from pulse generators
155 and 156, respectively. Denoted at 157 is a subsidiary CPU which is communicated
with the main controller 191 through the common bus 190 and which serves to control
the pulse generators 155 and 156 through a local bus 158. Denoted at 161 is an X-ray
detector, and denoted at 162 is a detector signal processing unit.
[0038] Denoted at 171 is a Y guide bar for guiding the Y stage 122, and it is fixed to a
main frame 172. The main frame 172 is fixed to the chamber 105 through an upper support
173 and a lower support 174. Denoted at 175 is a frame base, and the chamber 105 is
supported by actuators 176 - 178 provided at three locations on the chamber top (at
front side and rear left and rear right sides of the top). The attitude of the chamber
105 can be controlled by these actuators. Adjacent to these actuators 176 - 178, there
are provided three distance sensors 179 - 181. By measuring through these sensors
179 - 181 the distances to the frame base 175 from the mounting positions of these
sensors, respectively, the attitude of the chamber 105 can be detected. Denoted at
182 is a driver for driving the actuators 176 - 178. Denoted at 183 is a main assembly
attitude control unit which serves to detect the attitude of the chamber 105 on the
basis of the outputs from the sensors 179 - 181 and to control the attitude of the
chamber 105 through the drive of the driver 182.
[0039] Denoted at 191 is a main controller which serves to control the operation of the
exposure apparatus as a whole through the common bus 190, in accordance with the content
memorized in a memory 192.
[0040] Figure 2 is a perspective view schematically showing the exposure shutter device,
comprising the auxiliary shutter unit 106 and the main shutter unit 107 of Figure
1, as well as some elements necessary for explaining the function of the exposure
shutter device. In non-exposure period, the exposure beam 103 is blocked in the auxiliary
shutter unit 106, as shown in Figure 2, by an auxiliary shutter belt 201 which is
provided by a steel belt made of stainless steel. In the exposure period, on the other
hand, the exposure beam 103 goes through a front opening 202 formed in the auxiliary
shutter belt 201 as well as a rear opening 203 of the auxiliary shutter belt, moved
to a position approximately opposed to the front opening 202, and the exposure beam
arrives at a main shutter belt 221 of the main shutter unit 107 disposed behind the
auxiliary shutter belt 201. Like the auxiliary shutter belt 201 of the auxiliary shutter
unit 106, also the main shutter belt 221 is provided with two openings, namely, a
front opening 222 and a rear opening (not shown). The above-described function of
controlling local exposure time at each of different portions of the exposure region
in the Y direction is accomplished by controlling, at each portion in the Y direction,
the time period from the passage, through that portion, of a leading edge 223 of the
front opening 222 of the main shutter belt 221 to the passage of the trailing edge
(not shown) through that portion, so as to provide an inversely proportional relationship
between the time period and the illuminance of X-rays. In other words, the time period
is so controlled that, at different portions in the Y direction, the quantity of energy
absorption by the resist applied to the wafer is regular and correct.
[0041] The auxiliary shutter belt 201 is tensioned between an auxiliary shutter driving
drum 204, driven by the auxiliary shutter motor 151, and an auxiliary shutter idler
drum 205, and it is driven through the friction between the inside surface of the
shutter belt 201 and the outside surface of the driving drum 204. In order to assure
stable driving of the shutter belt 201 so as to avoid snaking, the driving drum 204
is crowned such that the diameter at the central portion of the drum with respect
to the widthwise direction is made larger by 50 - 100 microns than the diameter at
the end portion. The shutter belt 201 is provided with small rectangular slits 208
and 211, formed in the neighborhood of the left-side and right-side edges thereof,
for the position detection and the timing detection, respectively. These slits cooperate
with a photointerruptor 209 and a reflection sensor 210, respectively, to produce
a start signal for the driving of the auxiliary shutter motor 151 to be made in accordance
with a predetermined drive pattern, or to discriminate whether the exposure beam 103
is allowed to pass or is blocked.
[0042] The main shutter device has a similar mechanical structure as of the auxiliary shutter
device, described above.
[0043] Denoted at 231 is a pinhole formed in a front face of a detection portion of the
X-ray detector 161, which is mounted to the X stage 121 (see Figure 1).
[0044] X-ray intensity profile such as at 1i (2i) in Figure 3A can be measured by bringing
the two shutter units 106 and 107 into open states, respectively, and by moving the
Y stage 122 (see Figure 1) so as to scanningly displace the X-ray detector 161 in
the Y direction within the exposure view angle (exposure region). On the basis of
measured data, drive tables 1a and 1b (2a and 2b) such as shown in Figure 3B for the
leading edge 223 and the trailing edge (not shown) can be prepared, and corrected
drive such as shown in Figure 3C for attaining constant quantity of energy absorption
by the resist in the exposure region can be executed.
[0045] In this occasion, the X-ray intensity profile measurement is made on the basis of
a coordinate system of the X-ray detector 161 (X-Y coordinate system,of the wafer
stage, comprising X stage 121 and Y stage 122, as measured through the laser length-measuring
device 128). On the other hand, the corrected drive of the shutter is made on the
basis of a shutter drive coordinate system (x-y coordinate system of the drive table).
For this reason, if there is a deviation between these coordinate systems, it is not
possible to accomplish proper drive correction. In the present embodiment, in consideration
thereof, after a drive table representing the position (Y) versus passage time (t)
relation of each edge with respect to the wafer stage coordinate system is prepared
on the basis of the profile measured data, the relationship between the wafer stage
coordinate system and the shutter drive coordinate system is detected and conversion
is made to the position coordinate of the edge, from a coordinate value Y with respect
to the wafer stage coordinate system into a coordinate value y with respect to the
shutter drive coordinate system. By this, the drive table is converted into a table
that represents the position (y) versus passage time (t) relation of the edge with
respect to the shutter drive coordinate system, and, as a result, precise exposure
quantity correction is assured.
[0046] Details of such coordinate system conversion in this exposure apparatus will now
be explained. The coordinate system conversion may be executed together with the profile
measurement, at the time of assembling of the exposure apparatus, at the time of setting
of the same or at the time of maintenance thereof (in maintenance mode).
[0047] Referring to the flow chart of Figure 4, first, at step 401, the main shutter belt
221 is stopped at such position that, as shown in Figure 7, the leading edge 223 of
the opening 222 of the main shutter belt 221 blocks a portion of the exposure view
angle. It is assumed that the shutter drive coordinate at this time is y
N. In Figure 7, denoted at 701 is an illuminance detecting area corresponding to the
exposure view angle; at 702 is a high-precision reflection type sensor at the main
shutter unit 107 side (see Figure 1); at 703 is a slit which is . cooperable with
the high precision reflection type sensor 702 to determine an origin of the coordinate
system representing the position of the edge 223; and at 704 is the shadow of the
edge 223. At step 402 in Figure 4, the wafer stage is moved so as to scanningly displace
the X-ray detector 161 in the Y direction to thereby detect the wafer stage coordinate
(the position with respect to the illuminance distribution measurement coordinate
system) Y
N of the shadow 704 of the edge 223 (Figure 7).
[0048] Figure 8 illustrates the relationship between the Y-direction position of the pinhole
231 of the X-ray detector 161 and the output of the X-ray detector 161. In this drawing,
reference character Y
N denotes the position of the shadow of the edge 223, and a broken line depicts the
exposure profile to be defined in the region blocked by the shutter 221, which otherwise
is exposed with the exposure beam 103 when the shutter is open. Enlarging the portion
near Y
N in Figure 8 in the Y direction, the change in the output depending on the relationship
between the shadow Y
N of the edge and the pinhole 231 at the front face of the X-ray detector 161 is such
as shown in Figure 9. In Figure 9, reference character P
0 denotes the position of the pinhole 231 just at the moment as the pinhole 231 goes
out of the shadow 704 of the edge 223. Reference character P
N denotes the position of the pinhole 231 at which the center of the pinhole coincides
with the shadow 704 of the edge 223. Reference character P
S denotes the position of the pinhole 231 just at the moment as the pinhole 231 is
completely shaded by the shadow 704 of the edge 223. It is seen from Figure 9 that
accurately the position Y
N of the shadow 704 of the edge is at the middle point (ΔY
1 = ΔY
2) between a coordinate Y
0 corresponding to the position P
0 and a coordinate Y
S corresponding to the position P
S. In this embodiment, in consideration thereof, the middle point between the coordinate
Y
S at the rise of the output of the X-ray detector 161 and the coordinate Y
0 at the saturation point of the detector output is determined as the coordinate (edge
position) Y
N corresponding to the end line of the shadow 704 of the edge 223.
[0049] When the pinhole 231 is at the position P
N, the output of the X-ray detector 161 is not always equal to a half of the output
when the pinhole 231 is at the position P
0, i.e., E
1 ≠ E
2. This is because the output component based on the edge position and the component
based on the illuminance distribution (profile) are not discriminated separately.
[0050] Referring back to Figure 4, at step 403, the motor 152 is driven so that the leading
edge 223 is moved to a position, blocking another portion of the exposure view angle
701, namely, to a position of a shutter drive coordinate y
M. Then, at step 404, like step 402, a wafer stage coordinate Y
M of the shadow 704 of the edge 223 is detected.
[0051] When the wafer stage coordinates Y
N and Y
M corresponding to the shutter drive coordinates y
N and y
M at two different points in the exposure view angle 701, spaced in the Y direction,
are detected in the manner described above, then at step 405, the coordinate of the
edge position in the drive table of edge position (Y) versus passage time (t) relation
with respect to the wafer stage coordinate system, having been calculated on the basis
of the profile measured data and having been memorized into the memory 192, is converted
from a coordinate Y with respect to the wafer stage coordinate system into a coordinate
y with respect to the shutter drive coordinate system, by using the following equation:

By this, the drive table is converted into one that represents the position (y) versus
passage time (t) relation of the edge with respect to the shutter drive coordinate
system. Then, by using the obtained table, the main shutter unit 107 is controlled
and the exposure process of the wafer 110 to the mask 108 with the exposure beam 103
is executed. The table obtained by the conversion is memorized also into the memory
192.
[0052] In the foregoing example, the shadow of the leading edge 223 is detected and the
coordinate system of the illuminance distribution detector is converted into a coordinate
system of the edge drive table. However, in place of detecting the shadow of the leading
edge 223 of the opening 222 of the main shutter belt 221, the shadow of the trailing
edge may be detected and the coordinate system conversion may be made accordingly.
[0053] Next, description will be made of a paralleling operation of the exposure apparatus.
Such paralleling operation may be executed at the time of assembling of the exposure
apparatus, at the time of setting of the exposure apparatus or at the time of maintenance
of the apparatus (in maintenance mode).
[0054] Referring to the flow chart of Figure 5, first, at step 501, while holding the shutter
in its open state, the wafer stage is moved to scanningly displace the X-ray detector
161 in the X and Y directions, and an illuminance distribution of a part of or the
whole of the exposure view angle 601 is measured. At step 502, from measured data,
a line or lines of constant illuminance (constant-intensity lines) are detected. Figures
6A - 6C show examples of manner of scan. Since the exposure beam 103 (see Figure 1)
has non-uniformness in intensity substantially only in the Y direction, where as shown
in Figure 6A the scan is made along a path 602 which includes a small distance in
the Y direction at a rightward end portion of the illuminance detection plane 601
as well as a small distance in the Y direction at a leftward end portion of the illuminance
detection area and when a straight line 605 is drawn to connect points 603 and 604
having the same measured values of illuminance, then the line 605 provides a constant-intensity
line. Figure 6B shows an example wherein, as compared with the scan method shown in
Figure 6A, the Y-direction scanning lengths at the leftward and rightward portions
are increased so as to obtain a larger number of constant-intensity lines 605a - 605e.
Figures 6C and 6D show examples wherein, as compared with the scanning methods of
Figures 6A and 6B, a larger number of Y-direction scanning lines are used. By using
multiple measuring points for obtaining a single constant-intensity line, even in
an occasion where a constant-intensity line is not straight, an approximate straight
line can be drawn on the basis of a least square method or the like to determine the
constant-intensity line with a reduced error. In Figure 6, denoted at 601 is the illuminance
detecting area; at 602 is the path of scan of the X-ray detector 161; at 603 and 604
are those points at which the X-ray detector 161 produces outputs of the same level;
and at 605 and 605a - 605e are constant-intensity lines.
[0055] Then, at step 503 in Figure 5, the main shutter motor 152 is driven to move and stop
the main shutter belt 221 at a position at which, as shown in Figure 7, the leading
edge 223 of the opening 222 of the main shutter belt 221 blocks a portion of the exposure
view angle 701. In Figure 7, denoted at 701 is the exposure view angle of a size corresponding
to or slightly smaller than the illuminance detecting area 601 in Figure 6. The illuminance
detecting area 601 is so set that it is larger than the exposure view angle 701 at
least with respect to the Y direction and that the whole exposure angle 701 is included
inside the illuminance detecting area 601, so as to allow measurement of the illuminance
at a portion around the exposure view angle 701 through the X-ray detector 161. Denoted
at 702 is a high-precision reflection type sensor at the main shutter unit 107 side
(see Figure 1), and denoted at 703 is a slit which is cooperable with the high-precision
reflection type sensor 702 to determine the origin of a coordinate system representing
the position of the edge 223. It is to be noted here that, at step 503, in place of
using the leading edge 223 of the opening 222 of the main shutter belt 221, the trailing
edge (not shown) thereof may be used to block a portion of the exposure view angle.
Subsequently, at step 504, the X-ray detector 161 on the wafer stage is used to measure
the position of the shadow 704 of the edge 223 in the Y direction, at two different
points spaced in the X direction, to thereby detect any inclination of the edge shadow
704 with reference to the X axis (Y axis) of the X-Y plane.
[0056] Figure 8 illustrates the relationship between the Y-direction position of the pinhole
231 of the X-ray detector 161 and the output of the X-ray detector 161. In this drawing,
reference character Y
N denotes the position of the shadow of the edge 223, and a broken line depicts the
exposure profile to be defined in the region blocked by the shutter 221, which otherwise
is exposed with the exposure beam 103 when the shutter is open. Enlarging the portion
near y
N in Figure 8 in the Y direction, the change in the output depending on the relationship
between the shadow Y
N of the edge and the pinhole 231 at the front face of the X-ray detector 161 is such
as shown in Figure 9. In Figure 9, reference character P
0 denotes the position of the pinhole 231 just at the moment as the pinhole 231 goes
out of the shadow 704 of the edge 223. Reference character P
N denotes the position of the pinhole 231 at which the center of the pinhole coincides
with the shadow 704 of the edge 223. Reference character P
S denotes the position of the pinhole 231 just at the moment as the pinhole 231 is
completely shaded by the shadow 704 of the edge 223. It is seen from Figure 9 that
accurately the position Y
N of the shadow 704 of the edge is at the middle point (ΔY
1 = ΔY
2) between a coordinate Y
0 corresponding to the position P
0 and a coordinate Y
S corresponding to the position P
S. In this embodiment, in consideration thereof, the middle point between the coordinate
Y
S at the rise of the output of the X-ray detector 161 and the coordinate Y
0 at the saturation point of the detector output is determined as the coordinate (edge
position) Y
N corresponding to the end line of the shadow 704 of the edge 223.
[0057] When the pinhole 231 is at the position P
N, the output of the X-ray detector 161 is not always equal to a half of the output
when the pinhole 231 is at the position P
0, i.e., E
1 ≠ E
2. This is because the output component based on the edge position and the component
based on the illuminance distribution (profile) are not discriminated separately.
[0058] In the manner described above, the edge position Y
N is detected at least at two locations including the leftward and rightward end portions
in the X direction. Subsequently, at step 505 in Figure 5, from the results of detection
of the edge position Y
N and the constant-intensity line or lines 605 determined beforehand, any inclination
of the leading edge 223 or the trailing edge 207 in the X-Y plane with respect to
the constant-intensity line 605 is determined. At step 506, discrimination is made
as to whether the inclination of the edge 223 with respect to the constant-intensity
line 605 is not greater than a predetermined. If not, the paralleling operation is
finished. If on the other hand the inclination is greater than the predetermined,
the sequence goes to step 507 whereat drive quantities for the actuators 176 - 178
(Figure 1) necessary for the paralleling of the edge 223 with the constant-intensity
line 605, are calculated. Then, at step 508, these actuators 176 - 178 are driven
and, after this, the sequence goes back to 501 and the operations at steps 501 - 506
are repeated. After completion of the paralleling operation, the wafer 110 is exposed
to the mask 108 with the exposure beam 103, while being controlled by the main shutter
107.
[0059] While the foregoing description has been made of an exposure apparatus wherein the
exposure beam 103 comprises SOR X-rays, the present invention is not limited thereto
but is applicable also to an exposure apparatus which uses an exposure beam comprising
g-line light, i-line light, an excimer laser light or the like.
[0060] While the invention has been described with reference to the structures disclosed
herein, it is not confined to the details set forth and this application is intended
to cover such modifications or changes as may come within the scope of the following
claims.
1. An exposure apparatus for use with a radiation source (101) which generates radiation
which has a generally non-uniform illumination distribution in a first direction with
respect to a predetermined exposure region (222); the apparatus comprising exposure
quantity correcting means (107,152,154) for setting an exposure time distribution
in accordance with the non-uniformity of illumination so as to enable a substantially
uniform exposure of the exposure region, the exposure quantity correcting means (107,152,154)
including shutter means (107) having a leading edge (223) effective to start exposure
of the exposure region (222) and a trailing edge effective to stop the exposure, characterised
by illumination distribution measuring means (161) for measuring an illumination distribution
in the exposure region (222), computing means (162,191) for calculating a constant-illumination
line on the basis of data measured by the illumination distribution measuring means
(161) and means (176-178,182) for rotating the exposure apparatus relative to said
radiation source (101) so that the constant-illumination line (605) and the leading
or trailing edge of said shutter means (107) are parallel to one another.
2. An apparatus according to claim 1, wherein the exposure quantity correcting means
(107,152,154) includes driving means (154) for driving the leading and trailing edges
of said shutter means (107) so that, in accordance with a drive curve corresponding
to the non-uniformity of illumination, the leading edge being moved through the exposure
region in the first direction in a manner which is independent of the manner in which
the trailing edge is moved in the first direction through the exposure region.
3. An apparatus according to claim 2, wherein the illumination distribution measuring
means (161) comprises a detector (161) and means (121,122) for moving the detector
(161) to measure the illumination at at least two points spaced-apart in a direction
transverse to the one direction.
4. An apparatus according to claim 3, wherein the moving means (121,122) is adapted to
scan the detector (161) back and forth in the one direction while moving the detector
(161) in the direction transverse to the first direction.
5. An apparatus according to claim 4, comprising means for determining the illumination
measured by the detector (161) at a number of points in each back and forth scan of
the detector (161).
6. An apparatus according to claim 4 or claim 5, wherein the moving means (121,122) is
adapted to scan the detector (161) back and forth a number of times in the first direction.
7. An apparatus according to claim 1 or claim 2, wherein the illumination distribution
measuring means (161) comprises a detector (161) mounted to a stage (121,122) for
moving a substrate (110) to be exposed.
8. An apparatus according to any one of claims 3 to 7, further comprising means (231)
for detecting, using the detector (161), a position of an edge of a shadow (704) produced
by one of the leading and trailing edges (223 and 207).
9. An apparatus according to any one of the preceding claims, wherein the radiation source
(101) comprises an x-ray source and the illumination distribution measuring means
(161) comprises an x-ray detector (161).
10. An apparatus according to claim 9, including the x-ray source (101) comprising a synchrotron
radiation source.
11. An apparatus according to any one of the preceding claims, wherein the exposure apparatus
comprises a major assembly, wherein the radiation source is provided separate from
the major assembly of the exposure apparatus, wherein the exposure quantity correcting
means (107,152,154) is mounted integrally on the major assembly of the exposure apparatus,
and wherein the rotating means (176-178,182) comprises driving means provided in a
supporting element for supporting the major assembly of the exposure apparatus.
12. An apparatus according to claim 7 including driving means (154) for driving the leading
and trailing edges of said shutter means (207) in accordance with a shutter coordinate
system, and said detector (161) is adapted to detect a position of an edge of a shadow
(704) defined by the leading or trailing edge with respect to a stage coordinate system
of said stage (121,122) different from said shutter coordinate system.
13. A method of adjusting an exposure apparatus for use with a radiation source (101)
for generating radiation which has a generally non-uniform illumination distribution
in a first direction with respect to a predetermined exposure region (222), which
method comprises the steps of setting an exposure time distribution in accordance
with the non-uniformity of illumination so as to enable a substantially uniform exposure
of the exposure region, wherein the exposure is started by a leading edge (223) of
a shutter means (107) and stopped by a trailing edge of said shutter means (107) characterised
by the steps of measuring an illumination distribution in the exposure region, calculating
a constant-illumination line on the basis of the measured illumination distribution
data and rotating the exposure apparatus relative to said radiation source (101) so
that the constant-illumination line and the leading or trailing edge of said shutter
means (107) are parallel to one another.
14. A method according to claim 13, including the steps of driving the leading and trailing
edges so that, in accordance with a drive curve corresponding to the non-uniformity
in illumination, the leading edge is moved through the exposure region in the first
direction in a manner which is independent of the manner in which the trailing edge
is moved through the exposure region.
15. A method according to claim 14, including the step of measuring the illumination distribution
by moving a detector (161) to measure the illumination at at least two points spaced-apart
in a direction transverse to the first direction.
16. A method according to claim 15, including the step of scanning the detector (161)
back and forth in the first direction while moving the detector in the direction transverse
to the first direction to enable the illumination distribution to be measured.
17. A method according to claim 16 wherein the illumination measured by the detector (161)
is determined at a number of points in each back and forth scan of the detector (161).
18. A method according to claim 16 or claim 17 wherein the detector (161) is scanned back
and forth a number of times in the first direction.
19. A method according to any one of claims 15 to 18 including the step of detecting,
using the detector (161), a position of an edge of a shadow (704) produced by one
of the leading and trailing edges (223 and 207).
20. A method according to any one of claims 13 to 19 wherein the radiation source (101)
is an X-ray source and the illumination distribution in the exposure region is measured
using an X-ray detector (161).
21. A method according to claim 20 wherein said X-ray source (101) is a synchrotron radiation
source.
22. A method according to claim 15 including the steps of driving the leading and trailing
edges of said shutter means (207) in accordance with a shutter coordinate system,
and detecting a position of an edge of a shadow (704) defined by the leading or trailing
edge with respect to a stage coordinate system of a stage (121,122) on which the detector
(161) different from said shutter coordinate system, said stage (121,122) being provided
for moving a substrate (110) to be exposed.
23. An exposure method comprising the method of any one of claims 13 to 22 and the step
of exposing a substrate to radiation from the radiation source (101).
24. A method of manufacturing a semiconductor device comprising the steps of claim 23
and fabricating a device using the substrate.
1. Belichtungsvorrichtung zur Verwendung mit einer Strahlungsquelle (101), die Strahlung
erzeugt, die eine im allgemeinen ungleichmäßige Beleuchtungsstärkeverteilung in einer
ersten Richtung in bezug auf einen vorbestimmten Belichtungsbereich (222) hat; wobei
die Vorrichtung eine Belichtungsmengenkorrektureinrichtung (107, 152, 154) zum Einstellen
einer Belichtungszeitverteilung gemäß der Ungleichförmigkeit der Beleuchtungsstärke
aufweist, um so eine im wesentlichen gleichmäßige Belichtung des Belichtungsbereiches
zu ermöglichen, wobei die Belichtungsmengenkorrektureinrichtung (107, 152, 154) eine
Verschlußeinrichtung (107) mit einer voreilenden Kante (223), die ein Beginnen der
Belichtung des Belichtungsbereiches (222) bewirkt, und einer nachlaufenden Kante umfaßt,
die ein Beenden der Belichtung bewirkt,
gekennzeichnet durch
eine Beleuchtungsstärkeverteilungsmeßeinrichtung (161) zum Messen einer Beleuchtungsstärkeverteilung
in dem Belichtungsbereich (222),
eine Recheneinrichtung (162, 191) zum Berechnen einer Linie mit konstanter Beleuchtungsstärke
auf der Grundlage von durch die Beleuchtungsstärkeverteilungsmeßeinrichtung (161)
gemessenen Daten und
eine Einrichtung (176-178, 182) zum Drehen der Belichtungsvorrichtung relativ zu der
Strahlungsquelle (101), so daß die Linie mit konstanter Beleuchtungsstärke (605) und
die voreilende oder die nachlaufende Kante der Verschlußeinrichtung (107) zueinander
parallel sind.
2. Vorrichtung nach Anspruch 1, wobei die Belichtungsmengenkorrektureinrichtung (107,
152, 154) eine Antriebseinrichtung (154) zum Antreiben der voreilenden und der nachlaufenden
Kante der Verschlußeinrichtung (107) umfaßt, so daß die voreilende Kante gemäß einer
der Ungleichmäßigkeit der Beleuchtungsstärke entsprechenden Antriebskurve durch den
Belichtungsbereich in der ersten Richtung in einer Weise bewegt wird, die unabhängig
von der Weise ist, in der die nachlaufende Kante in der ersten Richtung durch den
Belichtungsbereich bewegt wird.
3. Vorrichtung nach Anspruch 2, wobei die Beleuchtungsstärkeverteilungsmeßeinrichtung
(161) eine Erfassungseinrichtung (161) und eine Einrichtung (121, 122) zum Bewegen
der Erfassungseinrichtung (161) aufweist, um die Beleuchtungsstärke an zumindest zwei
Punkten zu messen, die in einer quer zu der einen Richtung verlaufenden Richtung beabstandet
sind.
4. Vorrichtung nach Anspruch 3, wobei die Bewegungseinrichtung (121, 122) zum hin- und
hergehenden Abtasten der Erfassungseinrichtung (161) in der einen Richtung angepaßt
ist, während die Erfassungseinrichtung (161) in der quer zu der ersten Richtung verlaufenden
Richtung bewegt wird.
5. Vorrichtung nach Anspruch 4, die eine Einrichtung zum Bestimmen der Beleuchtungsstärke
aufweist, die durch die Erfassungseinrichtung (161) an einer Anzahl von Punkten bei
jedem hin- und hergehenden Abtasten der Erfassungseinrichtung (161) gemessen wird.
6. Vorrichtung nach Anspruch 4 oder Anspruch 5, wobei die Bewegungseinrichtung (121,
122) angepaßt ist, die Erfassungseinrichtung (161) einige Male in der ersten Richtung
hin- und hergehend abzutasten.
7. Vorrichtung nach Anspruch 1 oder Anspruch 2, wobei die Beleuchtungsstärkeverteilungsmeßeinrichtung
(161) eine Erfassungseinrichtung (161) aufweist, die zum Bewegen eines zu belichtenden
Substrates (110) an einem Objekttisch (121, 122) montiert ist.
8. Vorrichtung nach einem der Ansprüche 3 bis 7, die desweiteren eine Einrichtung (231)
aufweist, die unter Verwendung der Erfassungseinrichtung (161) eine Position einer
Kante eines Schattens (704) erfaßt, die entweder durch die voreilende oder durch die
nachlaufende Kante (223 oder 207) erzeugt wird.
9. Vorrichtung nach einem der vorherigen Ansprüche, wobei die Strahlungsquelle (101)
eine Röntgenstrahlungsquelle aufweist und die Beleuchtungsstärkeverteilungsmeßeinrichtung
(161) eine Röntgenstrahlungserfassungseinrichtung (161) aufweist.
10. Vorrichtung nach Anspruch 9, die die Röntgenstrahlungsquelle (101) umfaßt, die eine
Synchrotronstrahlungsquelle aufweist.
11. Vorrichtung nach einem der vorherigen Ansprüche, wobei die Belichtungsvorrichtung
eine Hauptbaugruppe aufweist, wobei die Strahlungsquelle von der Hauptbaugruppe der
Belichtungsvorrichtung getrennt vorgesehen ist, wobei die Belichtungsmengenkorrektureinrichtung
(107, 152, 154) an der Hauptbaugruppe der Belichtungsvorrichtung einstückig montiert
ist und wobei die Dreheinrichtung (176-178, 182) eine Antriebseinrichtung aufweist,
die in einem Stützelement zum Stützen der Hauptbaugruppe der Belichtungsvorrichtung
vorgesehen ist.
12. Vorrichtung nach Anspruch 7, die eine Antriebseinrichtung (154) zum Antreiben der
voreilenden und der nachlaufenden Kante der Verschlußeinrichtung (207) gemäß einem
Verschlußkoordinatensystem umfaßt, und wobei die Erfassungseinrichtung (161) zum Erfassen
einer Position einer Kante eines Schattens (704) angepaßt ist, die durch die voreilende
oder die nachlaufende Kante in bezug auf ein Objekttischkoordinatensystem des Objekttisches
(121, 122) definiert ist, das von dem Verschlußkoordinatensystem verschieden ist.
13. Verfahren zum Justieren einer Belichtungsvorrichtung zur Verwendung mit einer Strahlungsquelle
(101) zum Erzeugen von Strahlung, die eine im allgemeinen ungleichmäßige Beleuchtungsstärkeverteilung
in einer ersten Richtung in bezug auf einen vorbestimmten Belichtungsbereich (222)
hat, wobei das Verfahren den Schritt Einstellen einer Belichtungszeitverteilung gemäß
der Ungleichmäßigkeit der Beleuchtungsstärke umfaßt, um so eine im wesentlichen gleichmäßige
Belichtung des Belichtungsbereiches zu ermöglichen, wobei die Belichtung durch eine
voreilende Kante (223) einer Verschlußeinrichtung (107) begonnen und durch eine nachlaufende
Kante der Verschlußeinrichtung (107) beendet wird,
gekennzeichnet durch
die folgenden Schritte:
Messen einer Beleuchtungsstärkeverteilung in dem Belichtungsbereich,
Berechnen einer Linie mit konstanter Beleuchtungsstärke auf der Grundlage der gemessenen
Beleuchtungsstärkeverteilungsdaten und
Drehen der Belichtungsvorrichtung relativ zu der Strahlungsquelle (101), so daß die
Linie mit konstanter Beleuchtungsstärke und die voreilende oder die nachlaufende Kante
der Verschlußeinrichtung (107) zueinander parallel sind.
14. Verfahren nach Anspruch 13, das den Schritt Antreiben der voreilenden und der nachlaufenden
Kante umfaßt, so daß die voreilende Kante gemäß einer der Ungleichförmigkeit der Beleuchtungsstärke
entsprechenden Antriebskurve durch den Belichtungsbereich in der ersten Richtung in
einer Weise bewegt wird, die unabhängig von der Weise ist, in der die nachlaufende
Kante durch den Belichtungsbereich bewegt wird.
15. Verfahren nach Anspruch 14, das den Schritt Messen der Beleuchtungsstärkeverteilung
umfaßt, indem eine Erfassungseinrichtung (161) zum Messen der Beleuchtungsstärke an
zumindest zwei Punkten, die in einer quer zu der ersten Richtung verlaufenden Richtung
beabstandet sind, bewegt wird.
16. Verfahren nach Anspruch 15, das den Schritt hin-und hergehendes Abtasten der Erfassungseinrichtung
(161) in der ersten Richtung umfaßt, während die Erfassungseinrichtung in der quer
zu der ersten Richtung verlaufenden Richtung bewegt wird, um das Messen der Beleuchtungsstärkeverteilung
zu ermöglichen.
17. Verfahren nach Anspruch 16, wobei die durch die Erfassungseinrichtung (161) gemessene
Beleuchtungsstärke an einer Anzahl von Punkten bei jedem hin- und hergehenden Abtasten
der Erfassungseinrichtung (161) bestimmt wird.
18. Verfahren nach Anspruch 16 oder Anspruch 17, wobei die Erfassungseinrichtung (161)
einige Male in der ersten Richtung hin- und hergehend abgetastet wird.
19. Verfahren nach einem der Ansprüche 15 bis 18, das den Schritt Erfassen einer Position
einer Kante eines Schattens (704) unter Verwendung der Erfassungseinrichtung (161)
umfaßt, die entweder durch die voreilende oder durch die nachlaufende Kante (223 oder
207) erzeugt wird.
20. Verfahren nach einem der Ansprüche 13 bis 19, wobei die Strahlungsquelle (101) eine
Röntgenstrahlungsquelle ist und die Beleuchtungsstärkeverteilung in dem Belichtungsbereich
unter Verwendung einer Röntgenstrahlungserfassungseinrichtung (161) gemessen wird.
21. Verfahren nach Anspruch 20, wobei die Röntgenstrahlungsquelle (101) eine Synchrotronstrahlungsquelle
ist.
22. Verfahren nach Anspruch 15, mit den Schritten Antreiben der voreilenden und der nachlaufenden
Kante der Verschlußeinrichtung (207) gemäß einem Verschlußkoordinatensystem und Erfassen
einer Position einer Kante eines Schattens (704), die durch die voreilende oder die
nachlaufende Kante in bezug auf ein von dem Verschlußkoordinatensystem verschiedenen
Objekttischkoordinatensystem des Objekttisches (121, 122) definiert ist, auf dem die
Erfassungseinrichtung (161) ist, wobei der Objekttisch (121, 122) zum Bewegen eines
zu belichtenden Substrates (110) vorgesehen ist.
23. Belichtungsverfahren, das das Verfahren nach einem der Ansprüche 13 bis 22 und den
Schritt Belichten eines Substrates mit einer Strahlung aus der Strahlungsquelle (101)
aufweist.
24. Verfahren zum Herstellen einer Halbleiterausrüstung, das die Schritte von Anspruch
23 und Fertigen einer Ausrüstung unter Verwendung des Substrates aufweist.
1. Appareil d'exposition destiné à être utilisé avec une source de rayonnement (101)
qui produit un rayonnement qui possède une distribution d'éclairement en général non
uniforme, dans une première direction par rapport à une région prédéterminée d'exposition
(222); l'appareil comprenant des moyens (107,152,154) de correction de la quantité
d'exposition pour régler une distribution du temps d'exposition en fonction de la
non-uniformité de l'éclairement afin de permettre une exposition essentiellement uniforme
de la région d'exposition, les moyens (107,152,154) de correction de la quantité d'exposition
comprenant des moyens obturateurs (107) comportant un bord avant (223) agissant de
manière à déclencher l'exposition de la région d'exposition (222) et un bord arrière
agissant de manière à arrêter l'exposition, caractérisé par des moyens (161) de mesure
de la distribution d'éclairement pour mesurer une distribution d'éclairement dans
la région d'exposition (222), des moyens de calcul (162,191) pour calculer une ligne
d'éclairement constant sur la base de données mesurées par les moyens (161) de mesure
de la distribution d'éclairement, et des moyens (176-178,182) pour faire tourner l'appareil
d'exposition par rapport à ladite source de rayonnement (101) de sorte que la ligne
d'éclairement constant (605) et le bord avant ou arrière desdits moyens obturateurs
(107) sont parallèles entre eux.
2. Appareil selon la revendication 1, dans lequel les moyens (107,152,154) de correction
de la quantité d'exposition comprennent des moyens d'entraînement (154) pour entraîner
les bords avant et arrière desdits moyens obturateurs (107) de sorte que, conformément
à une courbe d'entraînement correspondant à la non-uniformité de l'éclairement, le
bord avant est déplacé à travers la région d'exposition dans la première direction,
d'une manière qui est indépendante de la manière dont le bord arrière est déplacé
dans la première direction à travers la région d'exposition.
3. Appareil selon la revendication 2, dans lequel les moyens (161) de mesure de la distribution
d'éclairement comprennent un détecteur (161) et des moyens (121,122) pour déplacer
le détecteur (161) pour mesurer l'éclairement en au moins deux points distants dans
une direction transversale par rapport à la une direction.
4. Appareil selon la revendication 3, dans lequel les moyens de déplacement (121,122)
sont adaptés pour déplacer le détecteur (161) selon un balayage en va-et-vient dans
la première direction, tout en déplaçant le détecteur (161) dans la direction transversale
par rapport à la une direction.
5. Appareil selon la revendication 4, comprenant des moyens pour détecter l'éclairement
mesuré par le détecteur (161) en un nombre de points lors de chaque balayage en va-et-vient
du détecteur (161).
6. Appareil selon la revendication 4 ou 5, dans lequel les moyens de déplacement (121,122)
sont adaptés pour déplacer le détecteur (161) selon un balayage en va-et-vient un
certain nombre de fois dans la première direction.
7. Appareil selon la revendication 1 ou 2, dans lequel les moyens (161) de mesure de
la distribution d'éclairement comprennent un détecteur (161) monté sur une table (121,122)
pour déplacer un substrat (110) devant être exposé.
8. Appareil selon l'une quelconque des revendications 3 à 7, comprenant en outre des
moyens (231) pour détecter, en utilisant le détecteur (161), une position d'un bord
d'une ombre (704) produite par l'un des bords avant et arrière (223 et 207).
9. Appareil selon l'une quelconque des revendications précédentes, dans lequel la source
de rayonnement (101) comprend une source de rayons X, et les moyens (161) de mesure
de la distribution d'éclairement comprennent un détecteur de rayons X (161).
10. Appareil selon la revendication 9, incluant la source de rayons X (101) comprenant
une source de rayonnement synchrotron.
11. Appareil selon l'une quelconque des revendications précédentes, dans lequel l'appareil
d'exposition comprend un ensemble principal, et dans lequel la source de rayonnement
est prévue séparément de l'ensemble principal de l'appareil d'exposition, et dans
lequel les moyens (107,152,154) de correction de la quantité d'exposition sont montés
de façon intégrante sur l'ensemble principal de l'appareil d'exposition, et dans lequel
les moyens d'entraînement en rotation (176-178,182) comprennent des moyens d'entraînement
prévus dans un élément de support servant à supporter l'ensemble principal de l'appareil
d'exposition.
12. Appareil selon la revendication 7, comprenant des moyens d'entraînement (154) pour
entraîner les bords avant et arrière desdits moyens obturateurs (207) en fonction
d'un système de coordonnées de l'obturateur, et ledit détecteur (161) est adapté pour
détecter une position d'un bord d'une ombre (704) défini par le bord avant ou arrière
par rapport à un système de coordonnées de ladite table (121,122) différent dudit
système de coordonnées de l'obturateur.
13. Procédé pour régler un appareil d'exposition destiné à être utilisé avec une source
de rayonnement (101) servant à produire un rayonnement qui possède une distribution
d'éclairement en général non uniforme dans une première direction par rapport à une
région d'exposition prédéterminée (222), lequel procédé comprend les étapes consistant
à régler une distribution du temps d'exposition en fonction de la non-uniformité de
l'éclairement de manière à permettre une exposition essentiellement uniforme de la
région d'exposition, et dans lequel l'exposition est déclenchée par un bord avant
(223) de moyens obturateurs (107) et est arrêtée par un bord arrière desdits moyens
obturateurs (107), caractérisé par les étapes consistant à mesurer une distribution
d'éclairement dans la région d'exposition, calculer une ligne d'éclairement constant
sur la base des données mesurées de distribution d'éclairement et faire pivoter l'appareil
d'exposition par rapport à ladite source de rayonnement (101) de telle sorte que la
ligne d'éclairement constant et le bord avant ou le bord arrière desdits moyens obturateurs
(107) soient parallèles entre eux.
14. Procédé selon la revendication 13, comprenant les étapes consistant à entraîner les
bords avant et arrière de sorte que, conformément à une courbe d'entraînement correspondant
à la non-uniformité d'éclairement, le bord avant est déplacé à travers la région d'exposition
dans la première direction, d'une manière qui est indépendante de la manière dont
le bord arrière est déplacé à travers la région d'exposition.
15. Procédé selon la revendication 14, incluant l'étape consistant à mesurer la distribution
d'éclairement en déplaçant un détecteur (161) de manière à mesurer l'éclairement en
au moins deux points distants dans une direction transversale par rapport à la première
direction.
16. Procédé selon la revendication 15, incluant l'étape consistant à déplacer le détecteur
(161) selon un balayage en va-et-vient dans la première direction, tout en déplaçant
le détecteur dans la direction transversale par rapport à la première direction pour
permettre une mesure de la distribution d'éclairement.
17. Procédé selon la revendication 16, dans lequel l'éclairement mesuré par le détecteur
(161) est déterminé en un nombre de points lors de chaque balayage en va-et-vient
du détecteur (161).
18. Procédé selon la revendication 16 ou 17, dans lequel le détecteur (161) est déplacé
selon un balayage en va-et-vient un nombre de fois dans la première direction.
19. Procédé selon la revendication 15 à 18 incluant l'étape consistant à détecter, en
utilisant le détecteur (161), une position d'un bord d'une ombre (704) produite par
l'un des bords avant et arrière (223 et 207).
20. Procédé selon l'une quelconque revendications 13 à 19, dans lequel la source de rayonnement
(101) est une source de rayons X et la distribution d'éclairement dans la région d'exposition
est mesurée en utilisant un détecteur de rayons X (161).
21. Procédé selon la revendication 20, dans lequel ladite source de rayons X (101) est
une source de rayonnement synchrotron.
22. Procédé selon la revendication 15 incluant les étapes consistant à entraîner les bords
avant et arrière desdits moyens obturateurs (207) en fonction d'un système de coordonnées
de l'obturateur, et détecter une position d'un bord d'une ombre (704) définie par
le bord avant ou le bord arrière par rapport à un système de coordonnées d'une table
(121,122) sur laquelle est placé le détecteur (161), qui est différent dudit système
de coordonnées de l'obturateur, ladite table (121,122) étant prévue de manière à déplacer
un substrat (110) devant être exposé.
23. Procédé d'exposition comprenant un procédé selon l'une quelconque des revendications
13 à 22 et l'étape d'exposition d'un substrat à un rayonnement provenant de la source
de rayonnement (101).
24. Procédé pour fabriquer un dispositif à semiconducteurs comprenant les étapes de la
revendication 23 et la fabrication d'un dispositif en utilisant le substrat.